1. Field of the Invention
This invention relates to a nailing gun, especially to one provided with a single-and-continual shot changeover device possible to be operated with easiness, steadiness and without fail.
2. Description of the Prior Art
A conventional single-and-continual shot changeover device 10 for a nailing gun shown in FIGS. 1 and 2 is arranged between an air valve switch and a safety connect rod, including a trigger 11, an eccentric adjust rod 12 and an actuating member 13. The trigger 11 is positioned at one side of the gun body to face to the air valve switch, and the eccentric adjust rod 12 consists of a press plate 121, an eccentric rod 122, a rotatable button 123 and a recover spring 124. The eccentric rod passes through the trigger 11, fixed eccentrically between the press plate 121 and the rotatable button 123, with the actuating member 13 having one end pivotally connected with the eccentric rod 122. Normally the rotatable button 123 is elastically pushed on the press plate 121 by the recover spring 124, retreating inward. So when a user pulls the rotatable button 123 to move the press plate to compress the recover spring 124, the rotatable button can be rotated for adjusting, as shown in FIG. 3, rotating the eccentric rod 112, which then rotates eccentrically to move up the actuating member 13 so that the safety connect rod alters its position reversely to the eccentric rod 112. Then the rotating button 123 is released to go back to its original position by means of the resilience of the recover spring 124, finishing changeover operation of the changeover device 10.
When the actuating member 13 is positioned at the lower location, with the contacting portion of the actuating member 13 with the safety connect rod being small, it will instantly separate from the safety connect rod to carry out a single shot action whenever the trigger 11 is pulled back for firing. On the contrary, when the actuating member 13 is positioned at an upper location, with the contact portion of the actuating member 13 with the safety connect rod increased, it does not separate from the safety connect rod whenever the trigger is pulled back for firing, so it continually fires shots, not singly.
However, in handling the conventional changeover device for a nailing gun, it cannot be done with only one hand, but it must be done with the left hand holding the grip of the nailing gun or with the nailing gun put down for properly turned over, and with the right hand pulling out the rotatable button 123 beside the trigger 1 rotated for adjusting and then released. So its handling is not so convenient, and in addition, a user is obliged to use a large force to a finger in pulling out and rotating the rotatable button 123, with its exposed portion of the rotatable button 123 being very small for avoiding accidental collision to be rotated. Therefore, the finger may be liable to be damaged on its skin in its handling.